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Genetic differences in needle cast damage of Scots pine (Pinus sylvestris L.)
2016
Polmanis, K., Latvian State Forest Research Inst. Silava, Salaspils (Latvia);Latvia Univ. of Agriculture, Jelgava (Latvia) | Klavina, D., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Gaitnieks, T., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Baumanis, I., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Lazdins, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia)
The impact of climatic and genetic factors on needle cast damage, as well as relationship between the degree of damage and survival and growth of trees was evaluated in the study. The analysis was done in two series of experiments, both established in two locations in Latvia (central and eastern part). Needle cast damage (in 5 grade scale) as well as the height and height increment, diameter of root collar and survival of trees were assessed. Results suggest that the degree of needle cast damage was influenced by the genetic, as well as climatic factors, and also their interaction. The average degree of needle cast damage in experiment of open-pollinated families was 4.7 ± 0.01 in central and 4.6 ± 0.03 in eastern Latvia; in the experiment of control-crossed families it was 4.6 ± 0.02 in central and 3.4 ± 0.04 in eastern Latvia. The impact of genetics on the needle cast damage degree was statistically significant (p is less than 0.05), and this effect was observed when any of growth traits (diameter, height or height increment) was used as a covariate in analysis. Results suggest the potential to select more resistant families, since the genetic correlation of grade of the damage between locations was significant (r = 0.40 - 0.72) and therefore improve also the growth of trees, since the grade of the damage had a negative correlation with growth traits both at provenance and family mean level (r = -0.69 and r = -0.42; p is less than 0.01).
Afficher plus [+] Moins [-]Impact of wood ash and potassium sulphate fertilization on growth of Norway spruce stand on organic soil
2016
Okmanis, M., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Skranda, I., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Lazdins, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Lazdina, D., Latvian State Forest Research Inst. Silava, Salaspils (Latvia)
Wood based ash can be used as a liming material and fertilizer in forest, thus providing a solution for utilization of wood ash and formation of additional increment of trees, especially on organic soils, where lack of potassium and phosphorus is a well-known factor limiting the growth of trees. Yet, many studies have been made with adverse results mostly because of different soil types and species investigated. However, by now the best results on fertilization with wood ash have been found on drained peatlands, where some nutrient deficiencies have emerged. The aim of this study was to find out the growth response of Norway spruce on drained organic soils after spreading of potassium sulphate (K2SO4) and wood ash (WA). The experiment was carried out in three middle aged Norway spruce (Picea abies) stands on drained mineral and peat soil. Experiment consisted of three replications of each treatment in each stand including WA, K2SO4 and the control on 400 square meter sub-sample plots each. The diameter and height of trees were measured. The samples of increment cores were collected 4 years after fertilization to determine the additional volume increment, which varied from 8.5 m**3 haE-1 in WA plots and from 9.7 m**3 ha-1 to 17.2 m**3 haE-1 on K2SO4 plots. Both - the wood ash and potassium application - significantly increased the increment of Norway spruce on drained mineral and peat soil, although no significant differences were found between the treatments (p = 0.82, α = 0.05).
Afficher plus [+] Moins [-]The impact of land drainage on Nevezis River flow
2013
Taparauskiene, L., Aleksandras Stulginskis Univ., Akademija, Kauno reg. (Lithuania) | Maziliauskas, A., Aleksandras Stulginskis Univ., Akademija, Kauno reg. (Lithuania) | Miseckaite, O., Aleksandras Stulginskis Univ., Akademija, Kauno reg. (Lithuania)
Most of the regulated rivers are situated in the middle part of Lithuania. Approximately 90% of all agricultural lands are drained in the Basin of Nevezis River, which is one of the most sensitive basins in Lithuania due to the lack of water and potential anthropogenic pollution. The goal of the research is to assess the impact of drainage on Nevezis River flow. Following the data series of 62 years, it was determined that water balance of Nevezis Basin is characterized by negative water balance during May-September due to higher evapotranspiration than average precipitation amount of the same period. It was stated that the average annual flow coefficient of the whole 10th hydrologic region of Lithuania was 0.3 till reclamation. It decreased to 0.28 during the period of intensive reclamation; however, the average annual flow was 0.35 from the year 1980, i.e., it increased in comparison with the period till reclamation. The average flow coefficient of warm period was 0.10 till reclamation, and remained the same during the period of 1956-1980, while the data of 1981-1995 show that the average flow coefficient increased – 0.11. After assessing the meteorological conditions and soil water balance of the Basin of Nevezis River it might be stated that the primary reason of water lack in the basin is climatic conditions. Drainage systems can hardly have a significant impact on wateriness of Nevezis River.
Afficher plus [+] Moins [-]Effect of farm size on the productivity and longevity of Latvian brown cows
2014
Cielava, L., Latvia Univ. of Agriculture, Jelgava (Latvia);Latvian Rural Advisory and Training Centre, Ozolnieki parish, Ozolnieki municipality (Latvia) | Jonkus, D., Latvia Univ. of Agriculture, Jelgava (Latvia) | Paura, L., Latvia Univ. of Agriculture, Jelgava (Latvia)
One of most important traits in dairy farming is cow (Bos primigenius taurus) longevity. In last few years the length of productive life in Latvian dairy cow population significantly decreased. Cow longevity depends on a large amount of genetic and non-genetic factors. Data from 1037 excluded Latvian brown (LB) breed cows were included in the analysis. Cows were born in the period from the year 2002 to 2006 and a farm size was 9 – 163 cows per farm. Farms were dislocated in all main regions of Latvia. Average life length of cows excluded from the herd was 2463.0 days in small farms, 2234.6 days in medium size farms and 2089.5 days in large farms. Cows’ productivity in one life day in small farms was 5.9 kg energy corrected milk (ECM), in medium size farms 6.2 kg ECM and in large farms 6.5 kg ECM. Large farm cows had longer life length in days (p is less than 0.05), but higher productivity in one productive day (p is less than 0.05) and productivity in one life day.
Afficher plus [+] Moins [-]Productivity of harvesters in commercial thinnings in the forest stands of different composition of species
2014
Petersons, J., Latvia Univ. of Agriculture, Jelgava (Latvia)
The aim of the study is to ascertain how different compositions of stand species affect the work of the harvester in commercial thinning under Latvia’s conditions. The data of the harvester – time-tracking files (*.drf) have been used as a basis for the study, where productivity is expressed as the prepared amount of round timber in cubic meters in a unit of time – an hour (m**3 hE-1). The data were collected from 100 commercial thinning areas which were divided into three types depending on the composition of the species: pure pine stands, pure spruce stands and deciduous tree mixed stands (mixed with coniferous trees). All the data for the study were collected in the forests managed by JSC ‘Latvia`s State Forests’. By summarizing the data, it has been established that in pure pine stands the average volume of the stem to be removed is 0.092 m**3, in mixed stands – 0.085 m**3 and in pure spruce stands - 0.068 m**3. The research demonstrates that the harvester showed its highest productivity while working in pure pine stands – 3.96 m**3 hE-1, the second best result was achieved in the mixed stands – 3.67 m**3 hE-1, but the lowest rate was demonstrated in pure spruce stands – 3.09 m**3 hE-1. Significant differences were observed in the productivity of the harvester between pure pine and pure spruce stands. Comparing the calculations of standard deviations in the harvester productivity, it can be seen that they are the biggest in mixed stands, while the lowest rate is demonstrated in pure spruce stands.
Afficher plus [+] Moins [-]The consumer's choice of branded products conformity to national identity: case of Baltic States
2014
Bikernieks, A., Latvia Univ. of Agriculture, Jelgava (Latvia) | Eglite, A., Latvia Univ. of Agriculture, Jelgava (Latvia)
The aim of the paper is to show the general trend of consumption in the Baltic countries. The member states of the European Union attach great importance to the well-being, health and the promotion of healthy lifestyle. In order to be able to make decisions on the future plan of action, COBEREN (Consumer Behaviour Erasmus Network) carried out a project with an aim of studying the food consumption habits in the European Union countries. The obtained results show the consumer habits of each participating state, although not on the regional level. This study will look at the consumption habits in the Baltic countries and find out the nature of consumption in those three states. The statistical method – analysis of variance – was used to analyse the COBEREN data. The main conclusion is that consumers of the Baltic countries do not differ greatly in their consumption habits.
Afficher plus [+] Moins [-]Relationship between body condition score, milk productivity and live weight of dairy cows
2014
Petrovska, S., Latvia Univ. of Agriculture, Jelgava (Latvia) | Jonkus, D., Latvia Univ. of Agriculture, Jelgava (Latvia)
Live weight and body condition are indicators for dairy cow’s (Bos taurus) health, milk productivity and reproduction. Live weight and body condition are defined by genetic and non-genetic factors. These factors are dependent on dairy cows growing and welfare. The aim of research was to analyze body condition relationship with milk productivity and live weight. Data were collected from 49 different breed and lactation dairy cows. Research location was Latvia University of Agriculture Research and Study farm ‘Vecauce’. Data were collected from October 2013 to January 2014. Body condition score of all cows decreased from 2.8 ± 0.05 to 2.5 ± 0.04 points in research period. Milk yield increased from 35.6 ± 0.79 kg in the 1st recording to 40.9 ± 1.12 kg in the 2nd recording. Milk yield decreased in the 3rd recording (p is less than 0.05). Fat content was the lowest in the 2nd recording (35.5 ± 0.09 g kgE-1). Protein content was significantly different in the 1st and 2nd recordings (p is less than 0.05). Somatic cell changes were not significant. Body condition decreased of older lactation cows, but milk yield increased at the same time. Milk yield was significantly the greatest in red breed group, compared with Holstein black and white cows (51.1 ± 3.21 kg vs. 41.4 ± 0.78 kg; p is less than 0.05). Body condition score significantly affected live weight in such body condition score groups: less than 2.5 points, 2.75 to 3.0 points. Effect was not significant on live weight in body condition score 3.25 less than group. Milk productivity and quality traits were not affected by the body condition score (p is less than 0.05).
Afficher plus [+] Moins [-]Estimation of genetic parameters for growth traits of sheep population in Latvia
2013
Puste, A., Latvia Univ. of Agriculture, Jelgava (Latvia) | Kairisa, D., Latvia Univ. of Agriculture, Jelgava (Latvia) | Sarma, R., Latvia Univ. of Agriculture, Jelgava (Latvia)
The aim of the present study was to estimate variance and covariance components and genetic parameters for birth, weaning and yearling weights. The data were collected from lambs who born in period from 2007 to 2010 years and located in 58 pure-bred sheep herds in Latvia. Records of 11310 lambs from 160 rams and 4180 ewes for birth and weaning weight and on 3194 lambs from 134 rams and 2058 ewes for yearling weight were used in this study. The total number of individual pedigree was 18932. The fixed effects in the model were sex and type of birth, birth year and month and age of dam, because all growth traits were significantly affected by these fixed effects (p is less than 0.01, p is less than 0.05). Genetic parameters for growth weights were estimated by Restricted Maximum Likelihood (REML) procedure fitting three animal models including various combinations of maternal and herd effects. Based on the most appropriate fitted model which included additive genetic, maternal additive genetic and herd effect, direct heritability’s were estimated to be 0.26 ± 0.01, 0.29 ± 0.63, 0.29 ± 2.63, but maternal heritability’s 0.14 ± 0.00, 0.04 ± 0.19, 0.04 ± 0.94, respectively for birth, weaning and yearling weights. The results showed maternal and strong herd influence in this study, therefore inclusion of maternal and herd effects into the model for growth traits is necessary.
Afficher plus [+] Moins [-]Comparison of different solvents for isolation of phenolic compounds from horseradish (Armoracia rusticana L.) leaves
2013
Tomsone, L., Latvia Univ. of Agriculture, Jelgava (Latvia) | Kruma, Z., Latvia Univ. of Agriculture, Jelgava (Latvia)
Horseradish (Armoracia rusticana L.) is a perennial herb belonging to the Brassicaceae family and contains biologically active substances. The aim of the current research was to determine the most suitable extraction method and solvent for obtaining horseradish leaf extracts with high antiradical activity. For experiments fresh leaves of horseradish were extracted with seven different solvents: n-hexane, diethyl ether, 2-propanol, acetone, ethanol (95%), ethanolwater/acetic acid (80/20/1 v/v/v) and ethanol / water (80/20 by volume) using two extraction methods (conventional and Soxhlet). For all extracts, total phenolic, flavonoid content and DPPH˙, ABTS radical scavenging activity, and reducing power were determined using a spectrophotometric method. As the best solvent can be used ethanol. Total phenolic content and total flavonoid content was higher in Soxhlet extracts. Comparing to other plants, the proportion of flavonoids in the amount of total phenolics is average, and it increases by increasing the polarity of used solvent. It can be concluded that by using Soxhlet extraction method it is possible to obtain extracts that are effective antioxidants. A very strong and a strong correlation has been identified between levels of phenolic compounds and antioxidant capacities of the extracts.
Afficher plus [+] Moins [-]The effect of production and storage on the content of vitamin C in NFC orange juice
2013
Zvaigzne, G., Latvia Univ. of Agriculture, Jelgava (Latvia) | Karklina, D., Latvia Univ. of Agriculture, Jelgava (Latvia)
The traditional consumption of citrus juices as a breakfast beverage has historical ties to obtaining one’s daily requirement of vitamin C. Vitamin C is one of the most important vitamins found in citrus juices, including orange juice. The aim of the study was to determine the effect of processing and storage on the content of vitamin C in orange juice varieties of ‘Valencia’ and ‘Navel’ of orange juice. The content of vitamin C (mg 100 gE-1) was determined with the iodine method in freshly squeezed orange juices and in pasteurized and packaged in aseptic bags orange juices of ‘Valencia ‘and ‘Navel’ variety, after processing and during 24 weeks of storage at 20 ± 1 °C and 5 ± 1 °C. The study results showed that the average content of vitamin C in freshly squeezed orange juice ‘Valencia’ was found at 33.56 mg 100gE-1 but in freshly squeezed orange juice ‘Navel’ the content of vitamin C was higher than in ‘Valencia’ variety orange juice average at 46.18 mg 100gE-1. The loss of vitamin C for both orange juices on average about 7% during processing The storage study showed that after 24 weeks of storage at 5 ± 1 °C and at 20 ± 1 °C, in pasteurized orange juice ‘Valencia’ the content of vitamin C decreased by 9.83% and 19.73 respectively. In the pasteurized orange juice ‘Navel’ the content of vitamin C decreased by 8.53% and 15.24% respectively.
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